Corrosion under insulation (CUI) is a particular type of corrosion that can occur in insulated equipment (e.g., piping) due to moisture build-up on the external surface of the insulated equipment. CUI that remains undetected can cause severe damage to the equipment (e.g., equipment failure), and thereby result in the closure of a process unit that features the damaged equipment or even a shutdown of an entire facility if the CUI occurs in a particularly vital location. The precursor of CUI is the accumulation of moisture and the development of water patches underneath insulation layers of the equipment.
For insulated pipes, the structure of the pipe generally includes several layers, including (starting from the inside and moving outward): a compatible coating, the insulation material, and a metal jacket cladding. The insulation material in the equipment generally comprises fibrous material (e.g., glass/mineral wool) and/or cellular material (e.g., calcium silicate, polyurethane, polystyrene). The cladding acts as a protective barrier on the outside of the piping, protecting the pipe from the outside elements (e.g., weather). For example, the cladding helps to prevent the insulation from being exposed to rain or physical damages.
Conventionally, in order to inspect insulated equipment for CUI, the portion of the equipment to be inspected is stripped of its cladding and its insulation, and is then visually inspected to see if CUI exists. This current practice, however, is time consuming because locations along the equipment must be checked at random or on a schedule, as there is oftentimes no outward indication of CUI. Further, the current practice is costly, as the insulation must be replaced at every inspection location, regardless of whether CUI was discovered or not. Accordingly, there is a need for a more time-effective and cost-effective process for inspecting insulated equipment for CUI. The present invention addresses one or more of these and other needs.